Part II. Cascading Style Sheets (CSS)
2.1) What are Cascading Style Sheets :
Let's say you make yourself a website one day. Your new website starts out with only 5 pages but after a few months it has grown to 100 pages. You decide that you don't like the old color scheme and you want to change it. It will take a long time to change the colors on all 100 pages.
If you had used a stylesheet then you would have been able to change the colors in only the stylesheet file and they would be applied to all 100 pages immediately.